Parametric audio reproduction systems produce sound through the heterodyning of two acoustic signals in a non-linear process that occurs in a medium such as air. The acoustic signals are typically in the ultrasound frequency range. The non-linearity of the medium results in acoustic signals produced by the medium that are the sum and difference of the acoustic signals. Thus, two ultrasound signals that are separated in frequency can result in a difference tone that is within the 60 Hz to 20,000 Hz hearing range of humans.
Additional non-linearities in parametric audio reproduction systems occur at the transducers used to generate the ultrasound signals. Further distortion can be caused by various harmonics and other audio artifacts that are inherent in parametric reproduction. The inherent distortion in parametric reproduction processes caused by the various non-linearities and distortions has been problematic.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.